Sodium Thiosulfate Fixer Solution Longevity

Pioneer · Jul 17, 2021

I am certain this has been asked 1000 times already but my search skills were not up to the task of finding it.

How long will Hypo last in solution?

I mixed up a batch back in May and, using it as Fixer 1 and Fixer 2, I have run 4 prints through it. The last print was fixed in the last week of May. I don't see anything settling out and it has been stored in 500ml glass bottles that are about 1/2 inch or less from the top.

I guess I can cut a bit of film and test it but I thought someone may have some good info or a rule of thumb for how long you can expect these solutions to last on the shelf. I can usually fix 18 or so prints before I swap bottle one to bottle two but I haven't done any printing for a little while.

Anyway, thoughts??

revdoc · Jul 17, 2021

You mean something like a plain hypo fixer?

Two months, according to Lloyd Erlick, but it's going to depend on the specific circumtances and your requirements.

https://www.heylloyd.com/technicl/plain.htm

mshchem · Jul 17, 2021

My experience with fixer is as long as it's unused or lightly used, kept away from oxygen so you don't precipitate out Sulfur, it doesn't smell of hydrogen sulfide, I would use it. Obviously one wants to be sure, testing for the once in a lifetime print etc. I made some Kodak F6 (lower odor than regular F5) fixer, stored in absolutely full PET 1 L bottles for 6 months worked fine.

I use a PAKO belt dryer for fiber base prints, so I always use a hardening fixer (to keep prints from sticking to the belt), for decades the old stinky Kodak powdered fixer. Last 10 years I use Kodak rapid fixer with hardener, film strength, about 1 minute constant agitation.

I need to make a print rocker for 2 bath fixing with regular fixer.

Pioneer · Jul 17, 2021

Thanks.

I'll try it tomorrow on a toss away print to see how it works.

It is just plain homemade hypo, nothing fancy. I don't use it on film but it rinses out of variable contrast resin coated paper pretty quickly so I use it on my prints. I don't use it on film and I don't use it with fiber paper, too much headache. But it is cheap and easy to mix and it works great for this.

If it works tomorrow as it normally would have then I'll use it for a few more prints. Then I'll mix up another batch.

mshchem · Jul 17, 2021

Pioneer said:
Thanks.

I'll try it tomorrow on a toss away print to see how it works.

It is just plain homemade hypo, nothing fancy. I don't use it on film but it rinses out of variable contrast resin coated paper pretty quickly so I use it on my prints. I don't use it on film and I don't use it with fiber paper, too much headache. But it is cheap and easy to mix and it works great for this.

If it works tomorrow as it normally would have then I'll use it for a few more prints. Then I'll mix up another batch.

I bought some beautiful sodium thiosulfate crystals off an Ebay seller. It's not quite as perfectly clean as the old Kodak crystals that came in 5 lb bottles but it's close. And as you know "plain old" works perfectly well!

Pioneer · Jul 17, 2021

Yeah. 10 pounds at a $1.50 a pound makes a lot of fixer for very little money. It has gone up a little since I bought my last batch but it is still very inexpensive.

Alan9940 · Jul 18, 2021

I have a 5L jug of F-24 that's about 5 months old that I've used on quite a few sheets of 8x10. Just tested it, yesterday, with a strip of film and it's fine.

Mark Crabtree · Jul 18, 2021

Test it will a piece of exposed film and you can see how well it works. Much harder to tell with prints.

Louis Nargi · Jul 18, 2021

There is a test solution you can buy, two drops in the fixer, if it cloud up its not good. I mix two pounds of sodium thiosulfate per gallon and it lasts for 6 months> No hardner, but you can add a hardner if you like

Mark Crabtree · Jul 18, 2021

That test is for excess silver in the solution, but does not tell you the fixer is good, just that it has not been used past its capacity.

grain elevator · Jul 18, 2021

Shouldn't you add some sulfite to prevent oxydation?

DMJ · Jul 18, 2021

I bought a 15lb bag (penta) on Amazon $38 long ago and I thought it was cheap, now I see that $1.50/lb is the deal. I use it plain and one-shot. How much sulfite to keep it for reuse? Can Campdem tablets be used for this ?

Pioneer · Jul 18, 2021

I use about 30 grams of sodium sulfite per liter of hypo. That seems to prevent oxidation but you can certainly add more if needed. Sodium sulfite is something else I have a lot of on hand since I buy it in bulk as well. It goes in just about everything so I use it up a bit quicker.

john_s · Jul 18, 2021

DMJ said:
I bought a 15lb bag (penta) on Amazon $38 long ago and I thought it was cheap, now I see that $1.50/lb is the deal. I use it plain and one-shot. How much sulfite to keep it for reuse? Can Campdem tablets be used for this ?

Campden tablets are metabisulfite in tiny doses to help home brewers add SO2 in a controlled fashion. Metabisulfite will preserve plain hypo but you'd need quite a few Campden tablets. Better to go to the home brewer shop and buy sodium metabisulfite powder. It will make the simple fixer a bit acidic. I prefer to use sodium sulfite because it's not acidic.

DMJ · Jul 19, 2021

I actually asked because I used to make wine and brew, and still have some. It's 150ppm of SO/tablet, 550mg of potassium metabisulphite. I'd need the whole container for 1 liter of fixer : ).

Sodium Thiosulfate Fixer Solution Longevity

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